Tzu-Ching Lin

Leaf-like carbon nanotube/nickel composite membrane extended-gate field-effect transistors as pH sensor

A leaf-like carbon nanotube/nickel (CNT/Ni) composite nanostructure is used as the sensing membrane in an extended-gate field-effect transistor (EGFET) for the pH sensors is first developed using nanocomposite plating technique. While sensing pH within a range of 2-10, the leaf-like CNT/Ni EGFET exhibits a sensitivity of 59 mV/pH. This simple and low-cost sensing membrane can be applied in disposable biosensors.

Core-shell structure of a silicon nanorod/carbon nanotube field emission cathode

A novel core-shell structure of silicon nanorods/carbon nanotubes (SiNRs/CNTs) is developed for use in field emission cathodes. The CNTs were synthesized on SiNRs, using the Ag-assisted electroless etching technique to form the SiNRs/CNT core-shell structure. This resulting SiNRs/CNT field emission cathode demonstrated improved field emission properties including a lower turn-on electric field Eon (1.3 V/µm, 1 µA/cm2), a lower threshold electric field Eth (1.8 V/µm, 1mA/cm2), and a higher enhancement factor β (2347). These superior properties indicate that this core-shell structure of SiNRs/CNTs has good potential in field emission cathode applications.

Gas ionization sensors with CNT/Ni field cathodes

A simple and low cost method to fabricate gas ionization sensors with CNT/Ni field cathodes on corning glasses using composite plating technique was first developed. The field emission characteristics of the initial CNT/Ni field cathode showed a low turn-on electric field E<inf>on</inf> of about 1.2 V/µm with an emission current density of 1 µA/cm².It was found that the breakdown voltage (V<inf>b</inf>) of the H<inf>2</inf> gas was decreased as the pressure increased from 0.5 to 100 Torr. However; on the contrary, the V<inf>b</inf> of the O<inf>2</inf> gas was increased as the pressure increased. It was observed from the Raman spectra that I<inf>D</inf>/I<inf>G</inf> increased for both of the H<inf>2</inf> and O<inf>2</inf> gases. The full width half maximum (FWHM) around 1580 cm⁻¹ was also increased for both of the H<inf>2</inf> and O<inf>2</inf> gases. Moreover, a shoulder of 1620 cm⁻¹ appeared after the H<inf>2</inf> and O<inf>2</inf> gases sensing measurements. This phenomenon, indicating the degradation of the graphitization, was more obvious for the O<inf>2</inf> gas sensing. The fabrication of the ionization sensors with CNT/Ni field cathode was relatively simple and inexpensive and could be mass-produced.